Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "synchronize-time: Retry if chrony failed due to NTP issues"
  - synchronize-time: Retry if chrony failed due to NTP issues

    chrony randomly fails with the following issue

    TASK [synchronize-time : synchronize time]
    *************************************
    fatal: [controller00]: FAILED! => {"changed": true, "cmd": "chronyc -a 'burst 4/4' && chronyc -a makestep", "delta": "0:00:00.004991", "end":
    "2017-09-14 19:30:37.561972", "failed": true, "rc": 1, "start": "2017-09-14 19:30:37.556981", "stderr": "", "stdout": "200 OK\n503 No
    such source", "stdout_lines": ["200 OK", "503 No such source"],"warnings": []}

    As such, lets retry a few more times before giving up.

    Change-Id: I20767bb3031061c03c9ba8dbc65859c7312bfac9
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 890763b..2357c9d 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 890763baf32de0bab7985b55fe9f8d7c59c48dc0
+Subproject commit 2357c9d195173cb7cdf57ffcbc7e92cea73e0ff1